I found this idea in a cute website, I tried it with my preschool children and they absolutely love it and enjoy it.
The activity was so much fun and promoted lots of open- ended creativity. It's clean and reusable too. I cut out shapes in different colors, and children arrange them any way they wanted to. At one point we run out shapes and they cut out some more. Children were able to easily stick the pieces to the window by dipping them in a plate of water first. painting . What a fun day!!